The Hawkins grenade was in use from 1942 to about 1955 by the British Army and the Home Guard.
After the evacuation from Dunkirk in May/June 1940 it was realised that there was the need for a new anti-tank weapon. It was roughly four months later Captain Hawkins submitted a design for a hand thrown anti-tank mine. After successful trails the General Staff placed an initial order for 2.5 million Hawkins Grenades.
The grenade is 7 inches (178 mm) x 3.75 inches (95 mm) x 2.75 (70 mm). Made of steel it weighed 3lb (1.36 kg). It contained 2lb (0.91 kg) of either ammonal or TNT explosive and required a pressure of 10lb (4.54 kg) to set it off.
When a vehicle drove over the grenade, it cracked a chemical igniter and leaked acid onto a sensitive chemical, which detonated the explosive. Multiple grenades were often used to destroy tanks or disable their tracks, and the grenade could also be used as a demolition charge.
The grenade was designed so that it could either be thrown at a vehicle like an ordinary anti-tank grenade or used as an anti-tank mine. A number could be strung together in a 'daisy chain' at intervals of around two feet, and then placed across a road to damage an armoured vehicle. The Hawkins was also used in other roles, such as breaching walls. Its small size also meant that it could easily be placed into the 'web' of a railway line and when detonated could destroy a section of track.
The picture shows a drill grenade filled with an oily sand and sawdust mixture. It was manufactured in May 1944 and is marked H. E. S. (High Explosive Substitute).